What are the holes in the pictures called? They are usually found in sinks and tubs and their function is to prevent water from overflowing.

Photo of a sink, with small holes below the faucet

  • 6
    Although many answers below are "correct", you would be hard-pressed to find a native English speaker (aside from a plumber) who would know what they're called beyond something like "the overflow holes" or "those holes that keep the sink from overflowing". Commented Oct 6, 2016 at 18:59

5 Answers 5


Although I see nothing wrong with overflows proposed by the answers and people casually call it that way, since I see in the comments that it technically refers to the whole system, I'd like to suggest the compound noun overflow holes. I did a search and found out it's actually quite common. I found some posts in Home Improvement Stack concerning these holes, too.

There is even a cover which blocks the hole called overflow hole cover for cosmetic purposes (as JimmyJames mentioned in his comment). Besides, you might want to consider overflow drain that I already mentioned under Colin Fine's answer.

(Whole credit, though, should go to Colin Fine because he was the first to post the word overflow and made me go for it)

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    "Overflow holes" is, in this specific case, the best suggestion so far.
    – user5267
    Commented Oct 5, 2016 at 18:21
  • @Absolute Beginner glad you found it useful.
    – Yuri
    Commented Oct 5, 2016 at 18:28
  • 'overflow drain' is probably the most correct/clear term for this but it's synonymous with 'overflow hole' or just 'overflow'.
    – JimmyJames
    Commented Oct 5, 2016 at 20:28
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    on a side (plumbing) note, overflow covers do not block smells. They are cosmetic. It's the trap that blocks sewer odors. If you have smells coming from the overflow, you may have a pretty serious plumbing problem.
    – JimmyJames
    Commented Oct 5, 2016 at 20:31
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    @JimmyJames I'll consider that in my answer. Thanks for pointing that out.
    – Yuri
    Commented Oct 5, 2016 at 20:54

These items are called sink overflows and are a common feature on baths and sinks. They are present to prevent the sink from overflowing with water should the plughole be blocked (by a plug for example).

For more information, see this article on overflows on a website that sells sinks and faucets.

  • 3
    From the article that you linked (with some nice pictures!), it looks like "overflows" are more than just the holes - they have the pipe in the back connected between the holes and the drain. I think that the question was asking about the whole system but you might want to make it clear that an overflow is more than the holes we can see in the picture.
    – ColleenV
    Commented Oct 5, 2016 at 12:02
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    @ColleenV I think rather than a pipe it's often a formed part of the sink, especially for a ceramic one like the pictured one (it might be a pipe for metal ones or a bathtub - in particular if a bathtub drain system has a lever below the faucet to move the stopper, this goes through a pipe and the cover for the lever hardware will have a hole for water to enter) - the point is that it's a functional drain system.
    – Random832
    Commented Oct 5, 2016 at 16:14
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    @ColleenV The question clearly asks what they are called. And the question states they know what they holes do.
    – paparazzo
    Commented Oct 5, 2016 at 17:51
  • @Paparazzi this system an be known as either the overflow drainage system, or more simply, overflow plumbing. Either answer can be used , with the first being more technical and the second being more basic, using simpler terminology. Commented Oct 5, 2016 at 17:54
  • I'm going to move the plumbing discussion to chat because I think I lead the discussion astray a bit.
    – ColleenV
    Commented Oct 5, 2016 at 19:07

I would simply call those the overflow.

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    It would be nice to include a reference and an example of how to use it. For example, overflow - any outlet that enables surplus liquid to be discharged or drained off, esp one just below the top of a tank or cistern. The sink overflow can help divert a small amount of water, but its main purpose is to allow air into the drain when the sink is filled with water.
    – ColleenV
    Commented Oct 5, 2016 at 10:25
  • +1 oveflows or overflow drains.
    – Yuri
    Commented Oct 5, 2016 at 11:16
  • 1
    Also What is an overflow drain
    – Yuri
    Commented Oct 5, 2016 at 11:30
  • To my ear, "overflow" sounds more like the water that's overflowing, rather than the mechanism which prevents that from occurring. "Overflow drain" or "overflow holes" sounds more natural. Just my 2 cents Commented Oct 6, 2016 at 20:31
  • I've never heard "overflow drain". I wonder if this is chance, or whether it's a regional thing.
    – Colin Fine
    Commented Oct 7, 2016 at 12:59

If you look a the original patent, the inventor refers to them as overflow drain openings. A previous invention that was basically a standpipe that fit into the main drain called it an overflow drain opening as well.

  • An overflow for a molded plastic sink is formed of a molded plastic body having a smooth, hollow interior forming a watertight passageway. The lower region of the body has a through opening surrounding the main drain over an opening in the drain and is sealed to the sink and the drain, the upper region of the body is sealed to the sink around an overflow opening extending through the sink and into the body. The mid region of the body is spaced from the underside of the sink.
  • If it's plastic, it can't be the original patent for the original sink.
    – Hot Licks
    Commented Oct 30, 2016 at 0:47
  • These things have been around for a long time. The overflow standpipe was metal in laboratories I have used. Some interesting older pictures at the link below. - chestofbooks.com/home-improvement/construction/plumbing/…
    – KalleMP
    Commented Feb 23, 2017 at 7:53

It has a name, it’s called a porcelator.

TFD says: 1. A pipe used to remove excess water and/or to prevent flooding in certain sanitary fixtures, storage tanks, and plumbing fittings

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